21354253 has 4 divisors (see below), whose sum is σ = 21624640. Its totient is φ = 21083868.

The previous prime is 21354251. The next prime is 21354293. The reversal of 21354253 is 35245312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21354253 - 2¹ = 21354251 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135075 + ... + 135232.

It is an arithmetic number, because the mean of its divisors is an integer number (5406160).

Almost surely, 2^21354253 is an apocalyptic number.

It is an amenable number.

21354253 is a deficient number, since it is larger than the sum of its proper divisors (270387).

21354253 is an equidigital number, since it uses as much as digits as its factorization.

21354253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270386.

The product of its digits is 3600, while the sum is 25.

The square root of 21354253 is about 4621.0662189586. The cubic root of 21354253 is about 277.4351356659.

Adding to 21354253 its reverse (35245312), we get a palindrome (56599565).

The spelling of 21354253 in words is "twenty-one million, three hundred fifty-four thousand, two hundred fifty-three".